Washable impregnation compositions

ABSTRACT

Anaerobic and heat curing polymerizable impregnation compositions for sealing pourous articles are disclosed. The compositions contain glycerol, oxygenated glycerol or (meth)acrylate glycerol to improve the washability of the compositions in aqueous solutions. The compositions may contain other compounds to effect the curing characteristics of the sealants.

This application is a 371 of international application PCT/US00/20076,filed Jul. 21, 2000, which claims the benefit of U.S. ProvisionalApplication Ser. No. 60/144,896, filed Jul. 1, 1999.

FIELD OF THE INVENTION

The present invention relates generally to washable, polymerizablecompositions. More particularly, the present invention relates to suchcompositions curable through mechanisms, anaerobic and heat, for use asimpregnation sealants.

BRIEF DESCRIPTION OF RELATED TECHNOLOGY

Impregnation sealing of porosity in porous parts frequently is carriedout by introducing sealant compositions into the porosity under apressure differential, by vacuum techniques which are well known in theart.

Sealant compositions typically employed in these impregnationapplications include a wide variety of self-curing anaerobic sealants,e.g., the compositions described in U.S. Pat. Nos. 3,672,942; 3,969,552;Re. 32,240; and U.S. Pat. No. 4,632,945, which are curable throughfree-radical polymerization in the presence of suitable free-radicalinitiators, e.g., peroxy-type initiators, as well as thermal-curingsealants, e.g., the compositions described in U.S. Pat. Nos. 4,416,921and 4,416,921, as well as sealants which cure by both anaerobic and heatcure mechanisms.

One problem common to many impregnation sealants is the accumulation ofexcess sealant on the outer surface of parts. Excess sealant isremovable by normal abrasion or by contact with various liquids. Theremoval of extraneous or surface accumulation of anaerobic and heatcuring sealants from the parts is important because such residues canreadily contaminant the environment of porous parts. In addition, suchsurface sealant deposits may, by virtue of their thickness, cause theimpregnated product part to vary from the desired dimensionalspecifications. This often renders the part deficient or even uselessfor its intended function in applications requiring close dimensionaltolerances.

Furthermore, such surface sealant deposits may interfere with subsequentpainting, plating, or assembly operations or cause delamination ofapplied paint or plated films which frequently are performed on porousarticles subsequent to their impregnation. Specifically, such surfacesealant deposits may be removed during painting or plating operations,resulting in contamination of the baths used in such operations, and mayinterfere with the adhesion of paint, plating, and the lie to theimpregnated part.

To remove excess sealant from impregnated articles, agitated rinse timesof significant duration are required. The actual rinse time will dependupon, among other things, the nature of the article, such as porosity,and the washability of the uncured sealant in an aqueous solution. Oftensuch rinse operations are from about five to about twenty minutes, butactual rinse times for any particular article may be even longer induration. In addition, chemicals, such as surfactants or detergents, mayalso be added to the aqueous solution to facilitate the removal ofsealant deposits.

For example, U.S. Pat. No. 3,672,942 to Neumann et al. discloses ananaerobic impregnant comprising a free-radical polymerizable acrylateester monomer and free-radical polymerization initiator, which requiresan organic solvent, such as a halogenated hydrocarbon, to remove uncuredimpregnant from the outer surface of a porous article.

U.S. Pat. No. 3,969,552 to Malofsky et al. describes a washing processfor removing excess impregnant from the surface of the porous articleafter porosity impregnation. The disclosed impregnation compositioncomprises an acrylic anaerobic curing resin and a peroxy initiatortherefor. The wash solution is an aqueous solution of a nonionicsurfactant of specified formula which is necessary for the removal ofuncured impregnant.

U.S. Pat. No. Re. 32,240 to DeMarco describes a self-emulsifyinganaerobic composition for porosity impregnation applications, comprisingan anaerobically curing monomer such as an acrylic ester, a peroxyinitiator therefor, e.g., a hydroperoxide or perester, an anionic ornonionic surfactant which is dissolved in the composition and renders itself-emulsifying upon mixing with water.

U.S. Pat. No. 5,256,450 to Catena describes an anaerobic polymerizableacrylate composition which requires a mixture of three differentpolymerizable acrylates in specific amounts to obtain a composition thatcures and rinses without the use of organic solvents or surfactants.

The above-described anaerobic sealant compositions are typicallyimpregnated into the porosity of metal parts by vacuum and pressuretechniques. A vacuum removes air from the porosity of the metal parts.Sealant compositions are then introduced into the porosity under apressure differential using ambient pressure or elevated pressureconditions. After impregnation, an operation, such as a centrifugeoperation, removes excess surface sealant from the metal part. Evenafter such removal of gross surface accumulations of the impregnant,there is a significant amount of impregnant at the surface of the porousarticles, particularly in the vicinity of the pores. When the impregnantis anaerobically cured, the aforementioned surface accumulations as wellas the outermost layer of the impregnant in the pores of the article,particularly shallow surface pores, are in contact with oxygen, so thatsuch surface quantities of the impregnant are uncured or only partiallycured.

Remaining surface sealant or sealant trapped in blind holes of theimpregnated parts is typically removed in an agitated water rinse zone.The impregnated and water-rinsed parts may be transferred to anactivator zone in which the impregnated parts are contacted with acatalyst activator solution, to effect curing of the sealant material atthe entrance to the pores in the parts. This creates a hardened plug orcap of sealant material in the outer portion of the pore, trapping theresin for anaerobic self-cure.

Thereafter, the impregnated parts may be transferred to a final rinsezone for removal of the activator solution from the impregnated parts.This final rinse solution may be at elevated temperature, e.g., on theorder of about 50° C., to warm the impregnated parts for quick drying,and to accelerate curing of the anaerobic impregnant within the interiorporosity of the article, the rate of such cure increasing withincreasing temperature.

As a variation on the above-described impregnation system, it is knownto utilize a heat-curing resin in place of the anaerobically-curingresin, whereby the activating and final rinsing steps previouslydescribed are eliminated in favor of a hot rinse final step. In theheat-curing resin impregnation system, after impregnation and rinsing ofexcess surface material, the parts are contacted with hot water attemperatures on the order of about 50° C. to about 90° C. to cure theimpregnant resin.

Among the previously developed heat-curing impregnating compositions forsealing porous parts are the compositions disclosed in the patentsidentified and discussed below.

U.S. Pat. No. 4,416,921 to Dunn describes a heat-curing sealantcomposition which contains a polymerizable acrylic monomer, anazonitrile and an anionic or nonionic surfactant to render thecomposition self-emulsifying upon mixing with water.

U.S. Pat. No. 4,147,821 to Young describes a heat-curing sealantcomposition which contains (meth)acrylic monomer and a polyfunctionalacrylic monomer. An emulsifier is required to aid in the rinsing ofuncured sealant from the surface of a porous article.

Once the heat-curable impregnant composition is introduced into theporosity of the parts to be sealed, the parts are transferred to anagitated water rinse zone for removal of any remaining surfaceaccumulations of sealant or extraneous sealant which is trapped in blindholes of the impregnated parts. After removal of the excess sealant inthe agitated water rinse zone, the impregnated parts are passed to atank containing hot water, e.g., at a temperature of 90° C. to 150° C.,or other medium at elevated temperature which serves to cure the sealantcomposition in the porosity. Relative to anaerobic impregnantcompositions, heat-curable impregnant compositions may be effectivelyused with a minimum of monitoring and maintenance, with little or noaeration being required.

In all of the above-described impregnation compositions and systems,either organic solvents or specific surfactants are used to removeuncured sealant in a reasonable rinse time or specific multi-componentsealant compositions are used to avoid excessive rinse times.

Accordingly, there is a need to provide a heat-curable and/or ananaerobic impregnating sealant without these and other disadvantages.

SUMMARY OF THE INVENTION

The present invention provides washable compositions for sealing porousarticles which have improved washability characteristics and reducedrinsing requirements. The present compositions achieve lower rinse timeswhile producing improved surface cleaning of uncured polymer. Thecompositions of the present invention demonstrate utility in the sealingand/or aqueous rinsing operations, and obviate the conventional use ofmulti-component cleaning systems.

In particular, the present invention provides a sealant composition withimproved washability, thereby reducing the rinse duration, improved easeof use by eliminating the need for specific surfactants, and whichimprove surface cleanliness of the porous article.

In one embodiment of the present invention, the inventive compositionincludes a curable (meth)acrylate glycerol, and is self-emulsifying uponmixing with water to facilitate aqueous rinsing of uncured composition.The inventive composition further includes curing initiators and curingaccelerators to promote anaerobic or thermal curing through free radicalmechanisms.

In another embodiment of the present invention, the inventioncomposition includes a polymerizable composition and further includes acompound selected from the group consisting of glycerol, oxylatedglycerol, (meth)acrylate glycerol and combinations thereof which improvethe washability of the inventive sealants in aqueous solutions.

In one desirable embodiment, the inventive composition contains an(meth)acrylate glycerol which has at least one terminal (meth)acrylategroup to allow crosslinking of the meth)acrylate glycerols upon curing.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to a sealant composition with improvedwashability characteristics as compared to known sealant compositions.The present invention provides sealant compositions, the components ofwhich serve to provide washability and self-emulsificability to theoverall composition. These components may be included with the inventivesealant composition during the impregnation operation or may beincorporated during the water rinse operation to provide washability andself-emulsificability to the overall composition. Uncured sealant istypically removed from the surface of the porous article during theaqueous rinse portion of the sealing process. As used herein the term“washable” and its variants refer to the ability of a sealantcomposition to emulsify in an aqueous solution and be readily removedfrom unwanted areas of an article in the aqueous solution. Also, as usedherein the term “self-emulsificability” and its variants refer to theability of one liquid to form minute droplets in a second liquidresulting in a heterogeneous mixture of two liquid phases.

The present compositions employ an independent component selected fromthe group consisting of glycerol, oxylated glycerol, (meth)acrylateglycerol and combinations thereof as an additive to anaerobic or heatcurable polymerizable compositions. The polymerizable compositionincludes polyfunctional and monofunctional (meth)acrylate esters toeffectuate the polymerizable properties of the sealant. The inventivesealant compositions may contain other components to tailor thepolymerizing, curing or emulsifing properties of the compositions. Theinventive sealants also contain an initiator system and/or inhibitorsystems to provide controlled anaerobic or thermal curing mechanisms.These compositions have a variety of uses, including an impregnationcompositions, sealants, adhesives, coatings and the like. Oneparticularly desirable embodiment relates to impregnation sealantcompositions for porous parts.

The inventive compositions are generally curable by free-radicalmechanisms. Typically, anaerobic conditions or elevated temperaturecondition may be used. In impregnation applications, however, generallyanaerobic and/or thermal mechanisms are used. Furthermore, the inventivecompositions are self-emulsifying upon mixing with water to facilitatethe aqueous rinsing of an impregnated article.

In one embodiment of the inventive composition the washability andself-emulsificability enhancing component in the form of glycerol isincorporated into the resultant polymer backbone. This compositionincludes a curable (meth)acrylate glycerol component having the formula:

wherein R¹ is a substituted or unsubstituted C₁ to C₅ alkyl or acombination thereof, R² and R³ are independently selected from the groupconsisting of hydroxyl, (meth)acrylate and combinations thereof,provided that at least one R² is a (meth)acrylate, where q, s and t areindependently from about 0 to about 35; and a free radical initiatorcomponent or system for producing free radicals to initiate cure of saidcomposition. The short chain C₁ to C₅ alkyl groups, as compared tolonger chain alkyl groups, assist in the washability of the inventivecompositions. Longer chain alkyl groups can act negatively to retardemulsification. Desirably, R¹ is an ethyl, a propyl or combinationsthereof. The (meth)acrylate glycerol compositions produce cross-linkedpolymers upon curing which serve as effective and durable self-washingsealants. The free radical initiator component provides free radicalsfor both anaerobic or heat curing of the composition.

The inventive compositions may contain from about 50% to about 99%(meth)acrylate glycerol by weight of the total composition with thebalance including other materials, for instance, initiators, inhibitors,surfactants, inserts, for instance, non-reactive plasticizers, and thelike.

The (meth)acrylate glycerol compositions may be suitably prepared bycondensing hydroxyalkyl (meth)acrylate, such ashydroxyethy(meth)acrylate (HEMA), onto hydroxyl groups of an oxylatedglycerol, such as an oxylated glycerol of formula VI below.

In an alternate embodiment, the inventive compositions include aself-washing polymerizable di(meth)acrylate glycerol having the formula:

wherein R⁷ is an ethyl or propyl [alkyl] and R⁸ is hydrogen or methyl;and a free radical initiator component or system.

Furthermore, in still another embodiment the inventive sealantcomposition may include at least one crosslinkable polymer, a curingcomponent for said polymer and a compound selected from the groupconsisting of glycerol, oxylated glycerol, (meth)acrylate glycerol andcombinations thereof. Desirably, the polymerizable component has amajority of polyfunctional (meth)acrylate esters (hereinafter,poly(meth)acrylate esters). These polyfunctional esters producecross-linked polymers, which serve as effective and durable sealants,adhesives and coatings. While various (meth)acrylate esters may be used,desirable poly(meth)acrylate esters include those with the followinggeneral formula:

wherein R¹⁰ represents a radical selected from the group consisting ofhydrogen, lower alkyl of from 1 to about 4 carbon atoms, hydroxyalkyl offrom 1 to about 4 carbon atoms and

R⁹ is a radical selected from the group consisting of hydrogen, halogen,and lower alkyl of from 1 to about 4 carbon atoms; R¹¹ is a radicalselected from the group consisting of hydrogen, hydroxyl, and

and m may be 0 to 12, and desirably from 0 to about 6; n is equal to atleast 1, e.g., 1 to about 20 or more, and desirably between about 2 toabout 6; k is 1 to about 4; and p is 0 or 1.

The polymerizable poly(meth)acrylate esters corresponding to the abovegeneral formula are exemplified by, but not restricted to, the followingmaterials: di-, tri- and tetraethyleneglycol dimethacrylate,dipropyleneglycol dimethacrylate; polyethyleneglycol dimethylacrylate(PEGMA); di(pentamethyleneglycol) dimethacrylate; tetraethyleneglycoldiacrylate; tetraethyleneglycol di(chloracrylate); diglyceroldiacrylate; diglycerol tetramethacrylate; tetramethylene dimethacrylate;ethylene dimethacrylate; and neopentylglycol diacrylate. Combinationsand derivatives of these polyfunctional materials are contemplated.Monofunctional (meth)acrylate esters (esters containing one(meth)acrylate group) are also advantageously used in the presentcompositions. The most common of these monofunctional esters include thealkyl esters such as lauryl methacrylate. Many of the lower molecularweight alkyl esters are quite volatile, and frequently it is moredesirable to use a higher molecular weight homolog, such as decylmethacrylate or dodecyl methacrylate, or any other fatty acid acrylateesters, in (meth)acrylate-based impregnant compositions.

When monofunctional (meth)acrylate esters are employed in the presentcompositions, it is desirable to use an ester which has a relativelypolar alcohol moiety. Such materials are less volatile than lowmolecular weight alkyl esters and, in addition, the polar group tends toprovide intermolecular attraction in the cured polymer, thus producing amore durable seal. Desirably the polar group is selected from the groupconsisting of labile hydrogen, heterocyclic ring, hydroxy, amino, cyano,and halogen polar groups. Typical examples of compounds within thiscategory are cyclohexylmethacrylate, tetrahydrofurfuryl methacrylate,hydroxyethyl acrylate (HEMA), hydroxypropyl methacrylate (HPMA),t-butylaminoethyl methacrylate, cyanoethylacrylate, andchloroethylmethacrylate. Combinations of monofunctional (meth)acrylateare contemplated.

When poly(meth)acrylate esters and monofunctional (meth)acrylate estersare employed together in the present compositions, the ratio ofpoly(meth)acrylate esters to monofunctional (meth)acrylate esters on aweight basis is generally about 0.05:1 to about 20:1. Desirably, for usein impregnation compositions the ratio is about 5:1. Furthermore, theinventive curable (meth)acrylate glycerol compounds can be combined withsuch esters in amounts of about 0.1% to about 99% by weight of the totalcomposition. In other words, the washability of such esters can beimproved by combining various amounts of (meth)acrylate glycerol.

In yet another embodiment of the present invention, a glycerol or anoxylated glycerol is combined with polymerizable sealant compositions tofurther improve washability thereof. The oxylated glycerol may beincorporated into the sealant composition or may be added separatelyinto the aqueous rinse solution used to wash the sealant compositionsthereby aiding in the removal of uncured surface and extraneous sealantfrom the surface of the part.

The oxylated glycerols of the present invention have the formula:

wherein R⁵ is a substituted or unsubstituted C₁ to C₅ alkyl or acombination thereof and w, x and y are independently from about 0 toabout 35. Desirably, R⁵ is an ethyl, a propyl or combinations thereof.

When poly(meth)acrylate esters and monofunctional (meth)acrylate estersare employed together in the present compositions, the ratio ofpoly(meth)acrylate esters to monofinctional (meth)acrylate esters on aweight basis is generally about 0.05:1 to about 20:1. Desirably, for usein impregnation compositions the ratio is about 5:1. Furthermore, theinventive oxylated glycerols can be combined with such esters in amountsof about 0.1% to about 75% by weight of the total composition. In otherwords, the washability of such esters can be improved by combiningvarious amounts of oxylated glycerols.

The compositions of the present invention may be anaerobically curablethrough a free-radical mechanism, with an initiator being presenttherein, or an initiator system comprising a redox polymerizationinitiator (i.e., an ingredient or a combination of ingredients whichproduce an oxidation-reduction reaction, resulting in the production offree radicals). Suitable initiators include peroxy materials e.g.,peroxides, hydroperoxides, and peresters, which are capable of inducingpolymerization of the inventive compositions in the substantial absenceof oxygen, and yet not induce polymerization as long as oxygen ispresent. Organic hydroperoxides are the desirable peroxy materials witht-butyl hydroperoxide and cumene hydroperoxide being particularly usefulwith the inventive compositions.

In addition to initiator components, the composition of the presentinvention may include various initiator accelerators, as for examplehydroperoxide decomposition accelerators, when hydroperoxides are usedas cure initiators in the sealant material. Typical examples ofpotentially suitable accelerators include: tertiary amines such astributyl amine; sulfimides such as benzoic sulfimide (or saccharin);formamide; and compounds containing transition metals, such as copperoctanoate.

The inventive compositions may also be heat-curable compositions througha free-radical mechanism, with a heat-cure initiator being presenttherein, or an initiator system comprising a redox polymerizationinitiator (i.e., an ingredient or a combination of ingredients which atthe desired elevated temperature conditions, e.g. from about 90° toabout 150° C., produce an oxidation-reduction reaction, resulting in theproduction of free radicals). Suitable initiators may include peroxymaterials, e.g., peroxides, hydroperoxides, and peresters, which underappropriate elevated temperature conditions decompose to form peroxyfree radicals which are initiatingly effective for the polymerization ofthe inventive compositions.

Another useful class of heat-curing initiators comprises azonitrilecompounds which yield free radicals when decomposed by heat. Heat isapplied to cure the composition, and the resulting free radicalsinitiate polymerization of the inventive composition.

For example, azonitrile may be a compound of the formula:

wherein R¹² is a methyl, ethyl, n-propyl, iso-propyl, iso-butyl orn-pentyl radical, and R13 is a methyl, ethyl, n-propyl, iso-propyl,cyclopropyl, carboxy-n-propyl, iso-butyl, cyclobutyl, n-pentyl,neo-pentyl, cyclopentyl, cyclohexyl, phenyl, benzyl, p-chlorbenzyl, orp-nitrobenzyl radical or R¹² and R¹³, taken together with the carbonatom to which they are attached, represent a radical of the formula

wherein m is an integer from 3 to 9, or the radical

Compounds of the above formula are more fully described in U.S. Pat. No.4,416,921, the disclosure of which hereby is incorporated herein byreference.

Azonitrile initiators of the above-described formula are readilycommercially available, e.g., the initiators which are commerciallyavailable under the trademark VAZO® from E.I. DuPont de Nemours andCompany, Inc. (Wilmington, Del.), including VAZO® 52 (R¹²=methyl,R¹³=isobutyl), VAZO® 64 (R¹²=methyl, R¹³=methyl), and VAZO® 67(R¹²=methyl, R¹³ =ethyl), all such R¹² and R¹³ constituents beingidentified with reference to the above-described azonitrile generalformula.

A desirable azonitrile initiator is 2,2′-azobis(iso-butyronitrile) orAZBN.

The azonitrile may be employed in the inventive heat-curablecompositions in concentrations on the order of about 500 to about 10,000parts per million (ppm) by weight, desirably about 1000 to about 5000ppm.

Other (meth)acrylic monomer-based impregnant compositions of aheat-curable character may be employed in the broad practice of thepresent invention, including those disclosed in UK Patent Specifications1,308,947 and 1,547,801. As described in these references, the monomericimpregnant composition may contain suitable inhibitors serving torestrict or preclude the occurrence of polymerization of the monomer, attemperatures below those desired or recommended for heatcuring of theimpregnant composition.

The inventive impregnant compositions may also contain otherconstituents, such as: other co-monomer species, reactive diluents,pigments, surfactants, fillers, polymerization inhibitors, stabilizers,anti-oxidants, anti-corrosion additives, and the like. For example,surfactants may be combined with the inventive compositions or includedin the aqueous rinse solution. The use of surfactants and specificmaterials utilized for such purpose are more fully described in U.S.Pat. No. 3,969,552 and Re. 32,240, the disclosures of each of which areexpressly incorporated herein by reference. Suitable surfactants includeclasses of anionic surfactants, such as petroleum sulfonates, alkylsulfonates or alkylaryl sulfonates and nonionic surfactants, such as,ethoxylated alkyl phenols, ethoxylated linear secondary alcohols,polyoxyethylene or polyoxypropylene glycols.

The invention may be further understood with reference to the followingnon-limiting examples. Percent weights are per the total compositionunless otherwise specified.

EXAMPLES Example 1

An anaerobic sealant composition according to the present invention(Composition One) was prepared with the following formulation:

TABLE 1 Composition One WT % Triethyleneglycol dimethacrylate 74.00Lauryl methacrylate 15.00 Hydroxpropyl methacrylate  5.00 Surfactant 5.24 Fluorescence  0.02 Inhibitor  0.04 Benzosulfimide (saccharin) 0.30 t-butyl hydroperoxide  0.40 Total: 100.00 

A lapshear, such as a metal lapshear (1″×4″×{fraction (1/16)}″) inaccordance with ASTM D-1002, was coated with the above inventivecomposition. The coated lapshear was repeatedly dipped into roomtemperature tap water to clean the coated lapshear to yield a basedipping requirement to clean the lapshear. Glycerol dimethacry late wasthen combined with inventive Composition One at various levels as shownbelow and the cleaning procedure was repeated. As illustrated in thebelow results in Table 2, including glycerol dirnethacrylate in theComposition One increased the washability thereof, as evidenced in adecrease in dips required for cleaning. These compositions proved tohave particular efficacy as an impregnation composition.

TABLE 2 Glycerol Dimethacrylate Number of Dips into Incorporated intoInventive 27° C. Tap Water to Composition One, WT % Clean CoatedLapshear 0   50+ 1 35 3 35 5 35 7 25 9 20 15  20

Example 2

An anaerobic sealant composition according to the present invention(Composition Two) was prepared with the following formulation:

TABLE 3 Composition Two WT % Butanediol dimethacrylate 50.00 TriallylCyanurate 30.00 Lauryl methacrylate 19.04 Fluorescence  0.02 Inhibitor 0.04 Saccharin  0.30 70% t-butyl hydroperoxide  0.60 Total: 100.00 

A lapshear, as described above in Example 1, was coated with the abovecomposition. The coated lapshear was repeatedly dipped into roomtemperature tap water to clean the coated lapshear to yield a basedipping requirement to clean the lapshear. Glycerol dimethacrylate wasthen combined with inventive Composition Two at various levels as shownbelow and the cleaning procedure was repeated. As illustrated in theresults below, incorporating glycerol dimethacrylate late in thecomposition increased the washability thereof, as evidenced by thedecrease in number of dips required for cleaning. These compositionsproved to have particular as an impregnation composition.

TABLE 4 Glycerol Dimethacrylate Number of Dips into Incorporated intoInventive 27° C. Tap Water to Composition Two, WT % Clean CoatedLapshear 0   50+ 1 15 3 13 5 10 7  8 9  8

Example 3

The anaerobic sealant composition (Composition Two) of Example 2 wasused in the following washability study.

A lapshear, as described above in Example 1, was coated with the abovecomposition. The coated lapshear was repeatedly dipped into roomtemperature tap water to clean the coated lapshear to yield a basedipping requirement to clean the lapshear. Ethoxylated glycerol was thencombined with the sealant composition at various levels as shown belowand the cleaning procedure was repeated. As illustrated in the belowresults in Table 5, including ethoxylated glycerol in the compositionincreased the washability thereof, as evidenced by a decrease in thenumber of dips required for cleaning. These compositions proved to haveparticular efficacy as an impregnation composition.

TABLE 5 Ethoxylated Glycerol Number of Dips into Incorporated intoInventive 27° C. Tap Water to Composition Two, WT % Clean CoatedLapshear 0   50+ 1 40 3 20 5 13 7 13 9 10

Example 4

The anaerobic sealant composition (Composition Two) of Example 2 wasused in the following washability study.

A lapshear, as described above in Example 1, was coated with the abovesealant composition. The coated lapshear was repeatedly dipped into roomtemperature tap water to clean the coated lapshear to yield a basedipping requirement to clean the lapshear. Propoxylated glycerol wasthen combined with the sealant composition at various levels as shownbelow and the cleaning procedure was repeated. As illustrated in thebelow results in Table 6, including propoxylated glycerol in the sealantcomposition increased the washability thereof, as evidenced by adecrease in the number of dips required for cleaning. These compositionsproved to have particular efficacy as an impregnation composition.

TABLE 6 Propoxylated Glycerol Number of Dips into Incorporated intoInventive 27° C. Tap Water to Composition Two, WT % Clean CoatedLapshear 0   50+ 1 17 3 15 5 12 7 10 9 10

Example 5

An anaerobic sealant composition according to the present invention(Composition Three) was prepared with the following formulation:

TABLE 7 Anaerobic Inventive Composition Three Sealant, WT % Glyceroldimethacrylate 97.0 cumene hydroperoxide  3.0 Total: 100.0 

Two drops, or about 0.4 grams, of the inventive composition was placedon a lapshear, as described in Example 1. A second lapshear was placedover the inventive composition, and the two lapshears were clampedtogether. A fixture test was then preformed at periodic time intervals.For the fixture test the two lapshears were unclamped at a particulartime period. If the lapshears could move relative to one and the other,the inventive composition did not fully cure. The two lapshear would bereclamped until the next time interval. If the two unclamped lapshearscould not moved relative to one and the other, then the inventivecomposition did fully cure. As illustrated below results in Table 8, theinventive composition anaerobically cured and proved to have particularefficacy as an impregnation composition with improved washabilitycharacteristics.

TABLE 8 Inventive Room Temperature Composition Three Anaerobic Curing 1hour after assembly Not Cured 2 hours after assembly Not Cured 3 hoursafter assembly Not Cured 4 hours after assembly Fully Cured

Example 6

An anaerobic sealant composition according to the present invention(Composition Four) was prepared with the following formulation:

TABLE 9 Anaerobic Inventive Composition Four Sealant, WT % Glyceroldimethacrylate 96.7  cumene hydroperoxide 3.0 Benzosulfimide (saccharin)0.3 Total: 100.0 

Two drops, or about 0.4 grams, of the inventive composition was used fora fixture test, as described in Example 5, with two lapshears. Saccharinproved to be an effective accelerator for aerobically curing theinventive composition. As illustrated below results in Table 10, theinventive composition anaerobicly cured and proved to have particularefficacy as an impregnation composition with improved washabilitycharacteristics.

TABLE 10 Inventive Room Temperature Composition Four Anaerobic Curing 1hour after assembly Fully Cured

Example 7

An anaerobic sealant composition according to the present invention(Composition Five) was prepared by adding 1 gram of copper octanoate to100 grams of Inventive Composition Four of Example 6. Two drops, orabout 0.4 grams, of the inventive composition was used for a fixturetest, as described in Example 5, with two lapshears. Copper octanoateproved to be an effective accelerator for aerobically curing theinventive composition. As illustrated below results in Table 11, theinventive composition anaerobicly cured and proved to have particularefficacy as an impregnation composition with improved washabilitycharacteristics.

TABLE 11 Inventive Room Temperature Composition Five Anaerobic Curing 20minutes after assembly Fully Cured

Example 8

An anaerobic sealant composition according to the present invention(Composition Six) was prepared with the following formulation:

TABLE 12 Inventive Anaerobic Composition Six Sealant, WT % Glyceroldimethacrylate 77.0 Lauryl methacrylate 10.0 Hydroxpropyl methacrylate10.0 cumene hydroperoxide  3.0 Total: 100.0 

Two drops, or about 0.4 grams, of the inventive composition was used fora fixture test, as described in Example 5, with two lapshears. Asillustrated below results in Table 13, the inventive compositionanaerobicly cured and proved to have particular efficacy as animpregnation composition with improved washability characteristics.

TABLE 13 Inventive Room Temperature Composition Six Anaerobic Curing 1hour after assembly Not Cured 2 hours after assembly Not Cured 3 hoursafter assembly Not Cured 4 hours after assembly Not Cured 5 hours afterassembly Not Cured 6 hours after assembly Not Cured 7 hours afterassembly Partially Cured

Example 9

An heat curable sealant composition according to the present invention(Composition Seven) was prepared with the following formulation:

TABLE 14 Inventive Heat Curable Composition Seven Sealant, WT % Glyceroldimethacrylate 97.0 cumene hydroperoxide  3.0 Total: 100.0 

Two drops, or about 0.4 grams, of the inventive composition was placedon a lapshear, as described in Example 1. A second lapshear was placedover the inventive composition, and the two lapshears were clampedtogether. The assembly was placed in an oven and maintained at 121° C. Afixture test, as described in Example 5, was then preformed after onehour. As illustrated below results in Table 15, the inventivecomposition thermally cured at 121° C. and proved to have particularefficacy as an impregnation composition with improved washabilitycharacteristics.

TABLE 15 Inventive 121° C. Composition Seven Heat Curing 1 hour afterassembly Fully Cured

Example 10

A heat curable sealant composition according to the present invention(Composition Eight) was prepared with the following formulation:

TABLE 16 Inventive Heat Curable Composition Eight Sealant, WT % Glyceroldimethacrylate 96.7  cumene hydroperoxide 3.0 Benzosulfimide (saccharin)0.3 Total: 100.0 

Two drops, or about 0.4 grams, of the inventive composition was used fora fixture test, as described in Example 9, with two lapshears. Asillustrated below results in Table 17, the inventive compositionthermally cured at 121° C. and proved to have particular efficacy as animpregnation composition with improved washability characteristics.

TABLE 17 Inventive 121° C. Composition Eight Heat Curing 1 hour afterassembly Fully Cured

Example 11

A heat curable sealant composition according to the present invention(Composition Nine) was prepared with the following formulation:

TABLE 18 Inventive Heat Curable Composition Nine Sealant, WT % Glyceroldimethacrylate 77.0  Lauryl methacrylate 10.0  Hydroxpropyl methacrylate10.0  cumene hydroperoxide 3.0 Total: 100.0 

Two drops, or about 0.4 grams, of the inventive composition was used fora fixture test, as described in Example 9, with two lapshears. Asillustrated below results in Table 19, the inventive compositionthermally cured at 121° C. and proved to have particular efficacy as animpregnation composition with improved washability characteristics.

TABLE 17 Inventive 121° C. Composition Nine Heat Curing 1 hour afterassembly Fully Cured

The invention being thus described, it will be clear to those persons ofskill in the art that the same may be varied in many ways. Suchvariations are not to be regarded as a departure from the spirit andscope of the invention and all such modifications are intended to beincluded within the scope of the claims.

What is claimed is:
 1. A free-radical curable composition which iswashable and self-emulsifiable upon mixing with water comprising: (a) acurable glycerol composition having the formula:

wherein R¹ is a C₁ to C₅ alkylene; R² and R³ are independently selectedfrom the group consisting of hydroxyl, (meth)acrylate and combinationsthereof; q, s and t are independently from about 0 to about 35; providedthat at least one of said R² is said (meth)acrylate; at least one q, sor t, is not zero and that at least one of said R¹ is ethyl or propyl;and (b) a free radical initiator to initiate cure of said composition,wherein said free radical initiator includes a heat-curing initiator toproduce free radicals by thermal decomposition to cure said sealant. 2.The composition of claim 1 wherein the heat-curing initiator is selectedfrom the group consisting of a peroxide, a hydroperoxide, a perester, anazonitrile and combinations thereof.
 3. A free-radical curablecomposition which is washable and self-emulsifiable upon mixing withwater comprising: (a) a curable glycerol composition having the formula:

wherein R¹ is a C₁ to C₅ alkylene; R² and R³ are independently selectedfrom the group consisting of hydroxyl, (meth)acrylate and combinationsthereof; q, s and t are independently from about 0 to about 35; providedthat at least one of said R² is said (meth)acrylate; at least one q, sor t, is not zero and that at least one of said R¹ is ethyl or propyl;and (b) a free radical initiator to initiate cure of said composition,wherein said free radical initiator includes an anaerobic-curinginitiator to produce free radicals upon the exclusion of oxygen to curesaid sealant.
 4. The composition of claim 3 wherein saidanaerobic-curing initiator is a peroxy initiator selected from the groupconsisting of hydroperoxides, peroxides, peresters and combinationsthereof.
 5. The composition of claim 3 wherein said anaerobic-curinginitiator includes an anaerobic accelerator selected from the groupconsisting of tributyl amine, benzoic sulfimide, formamide, copperoctanoate and combinations thereof.
 6. The composition of claim 1further including a poly(meth)acrylate ester having the formula:

wherein R¹⁰ represents a radical selected from the group consisting ofhydrogen, lower alkyl of from 1 to about 4 carbon atoms, hydroxyalkyl offrom 1 to about 4 carbon atoms and

R⁹ is a radical selected from the group consisting of hydrogen, halogen,and lower alkyl of from 1 to about 4 carbon atoms; R¹¹ is a radicalselected from the group consisting of hydrogen, hydroxyl and

m is 0 to about 12, n is equal to at least 1, k is 1 to about 4 and p is0 or
 1. 7. The composition of claim 1 further including a monofunctionalacrylate ester, said monofunctional acrylate ester being selected fromthe group consisting of lauryl methacrylate, cyclohexylmetharylate,tetrahydrofurfuryl methacrylate, hydroxyethyl acrylate, hydroxypropylmethacrylate, t-butylaminoethyl methacrylate, cyanoethylacrylate,chloroethylmethacrylate and combinations thereof.
 8. The composition ofclaim 1 further including an ionic surfactant, an anionic surfactant andcombinations thereof.
 9. The composition of claim 1 wherein R¹ is ethyl,propyl or a combination thereof.
 10. A method of anaerobically orthermally sealing a porous article comprising: (a) selecting a curableglycerol composition having the formula:

wherein R¹ is a C₁ to C₅ alkyl or combinations thereof; R² and R³ areindependently selected from the group consisting of hydroxyl,(meth)acrylate and combinations thereof; q, s and t are independentlyfrom about 0 to about 35; provided that at least one of said R² is said(meth)acrylate; at least one q, s or t, is not zero and that at leastone of said R¹ is ethyl or propyl; and (b) selecting a free radicalinitiation to initiate curing of said curable glycerol; (c) impregnatingpores of said article with said curable glycerol and said initiator, and(d) washingsaid curable glycerol from a surface of said article in awash tank containing an aqueous solution.
 11. The composition of claim 3further including a poly(meth)acrylate ester having the formula:

wherein R¹⁰ represents a radical selected from the group consisting ofhydrogen, lower alkyl of from 1 to about 4 carbon atoms, hydroxyalkyl offrom 1 to about 4 carbon atoms and

R⁹ is a radical selected from the group consisting of hydrogen, halogen,and lower alkyl of from 1 to about 4 carbon atoms; R¹¹ is a radicalselected from the group consisting of hydrogen, hydroxyl and

m is 0 to about 12, n is equal to at least 1, k is 1 to about 4 and p is0 or
 1. 12. The composition of claim 3 further including amonofunctional acrylate ester, said monofunctional acrylate ester beingselected from the group consisting of lauryl methacrylate,cyclohexylmetharylate, tetrahydrofurfuryl methacrylate, hydroxyethylacrylate, hydroxypropyl methacrylate, t-butylaminoethyl methacrylate,cyanoethylacrylate, chloroethylmethacrylate and combinations thereof.13. The composition of claim 3 further including an ionic surfactant, ananionic surfactant and combinations thereof.
 14. The composition ofclaim 3 wherein R¹ is ethyl, propyl or a combination thereof.